Propeller mechanism



Jan. 20, 1953 K. L. BERNINGER ET AL 2,

PROPELLER MECHANISM Filed June 8, 1946 5 Sheets-Sheet l g 60 .56 4 QM: 4% \.L\ 54 s '7 INVENTORS 44 g ZZ KENNETH 1.. an? 1mm g 5 dOH/V FHA/J E6 .7166 ATTORNEYS 1953 K. L. BERNINGER ET AL 2,625,998

' PROPELLER MECHANISM Filed June 8, 1946 3 Sheets-Sheet 2 -J 5 INVENTOR5 ATTORNEYS Patented Jan. 20, 1953 PROPELLER MECHANISM Kenneth L. Berninger and John F. Haines, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application June 8, 1946, Serial No. 675,391

Claims. 1

This invention relates to aircraft propellers, and has for an object to provide a propeller construction with variable pitch blades, which propeller construction is small, compact, simple of fabrication, from conventional structural elements, and provides propellers with variable pitch, at relatively low cost.

Another object of the invention is to provide a control means for a pitch shiftable propeller so that constant speed for take-off is assured by automatic governor mechanism, and high pitch blade setting is assured through a fixed angle for cruising flight.

Another object of the invention is to provide an automatic governor valve for a propeller controlling fluid circuit that will control the decreased pitch pressure.

Another object of the invention is to provide a flow sensitive valve to release fluid pressure when the pressure generating source becomes inoperative.

Another object of the invention is to provide a propeller with pitch shiftable blades, and a control mechanism for shifting the blades to either-one of two positions by developing a fluid pressure to oppose the natural or inherent tendencies of the blades to shift to a predetermined position of pitch setting.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a perspective view of a propeller hub with blades attached that incorporates the instant invention.

Fig. 2 is a transverse sectional view through the hub substantially as indicated by the line and arrows 2-2 of Figs. 1 and 5.

Fig. 3 is a section through the blade socket looking toward the root of the blade substantially as indicated by the line and arrows 33 of Fig. 2.

Fig. 4 is a sectional view through the propeller hub longitudinal of the driving shaft showing its support from the engine nosing or gear casing and disclosing means for continuously driving the power developing means when the propeller is rotating, the view being taken substantially as indicated by the line and arrows 44 of Fig. 2.

Fig. 5 is a similar sectional view but circumferentially displaced as indicated by the lines 55 of Figs. 2 and 6, so as to show the power developing means provided with the preferred form of means for selectively operating the power developing means and the governing means.

Fig. 6 is a, sectional view through the regulator mechanism of the propeller substantially as indicated by the line and arrows E6 of Figs. 4 and 5.

Fig. 7 is a schematic diagram illustrating the principle of operation and disclosing another form of means for selectively operating the power developing means.

With particular reference to the drawings and first considering Fig. 4, 10 indicates a gear casing or engine nosing from which extends a hollow rotatable propeller shaft I2 splined at [4 to drivingly engage splines l6 of a propeller hub sleeve I8 provided with sockets 20 for pitch shiftably mounting propeller blades 22. The hub sleeve [8 usually seats upon a rear cone element 24 where it is maintained by a forward split cone 26 being thrust into position by a hub shaft nut 28 locked in secured relation by the usual lock pin 29. Contributing to this end the hub sleeve [8 provides appropriate conic shoulders receptive of the cones 24 and 26.

In practising the invention herein disclosed and claimed, the propeller hub is fabricated from standard tubular steel products which may comprise a predetermined length of tubular material for providing the hub sleeve l8 and a second tubular section which is machined and fabricated and joined to the tubular sleeve Hi to provide the socket members 20. Toward this end the interior of the sleeve [8 is machined to provide the rearward conic seat engageable with the cone ring 24 and the bore of the tube is otherwise fashioned to provide the splines l6 and the crown seat for the forward cone 26. An extension with a large bore 30 permits assembly and manipulation of the cone 26 and nut 28. The forward extension 32 provided by the enlarged bore 30 forms a support for an annular regulator later to be described, and a rearward tubular extension 34 provides support for a housing enclosing power developing means later to be described. Exteriorly, the tubular portion I8 is turned or machined to difierent diameters which may incorporate a maximum diameter as at 36 with an aft reduced diameter at 38 and a further reduction at 40 which extends to the rear of socket tube 20 over the rear cone 24 for the extension 34. Forwardly of the main diameter 36 the tube may be diminished in outside diameter by successive steps to provide the thin wall for 32. It will be noted that the greatest body of materlal in this tubular length is disposed over the 3 interiorly splined section and at the portion shown to intersect with the tubular socket portion 29, see Figs. 4 and 5.

Working of the tubular portion 20 from a length of tubular stock incorporates bores transverse to the axis of the tube through which the portions 34, 36 and 38- of the tubular section l8- may be passed with a relatively tight fit. When that assembly is accomplished the parts may be secured together either by brazing, welding or such other furnace or heat treatment as will unite the tubular elements l8 and 20 into a rigid and substantially integral-like unit of structure. Thus; the tubes 18 and 20 will be securely bonded together at all junctures such as indicated" at 45. As shown particularly in Fig. 2, tubular section 20 has its end portions 23 exteriorly tapered and interiorly threaded at 46 to engage a blade retaining nut 48 forming an outer race member for a blade bearing comprising balls 50 rolling upon an inner race 52 carried by the shankend of the blade 22 and seated against a flange or shoulder 54 of the blade. Closing. the radially inward end of the blade 22 there is a head member 55 secured to the flangev portion 54 in driving relation by means of dowels or the like 58 and. a. center piece 60 inwardly engagesv a flat 62 to bottom the blade against the tubular section H3. The head member 56 has a lateral extension or arm 64 adapted to engage a thrust rod. 66 guided by a tubular sleeve 68 for altering. the pitch. of the blade as will presently be explained. Thus, it can be seen that the blades 22 are capable. of rotation about their axes upon the bearings 50' upon the variation of forces appliedto the lug 64'.

In the instant propeller constructionv the blades 22 are so constructed with respect. to their pitch changing axis that there is a normal tendency of the blade, upon propeller rotation, to turn: upon its axis in a direction to increase pitch. such as to maintain engagement with or to thrust. against the end of the shift rod 66'. That normal tendency may be built in provisions incorporating offcenter weights, or attached counterweights as is well known in the art, orthe provisions may result in sufficient sway-back. of the blade that. centrifugal force during. propeller rotation tends; to shift the blades on their. pitch axis; towardarr increase pitch position, a method which is. also known. by those experienced in. the art. On. the other hand, as shown in Fig. 7,. the normal tendency may be. incorporated in the; regulator where the chamber 92 is loaded with gas under.- pressure that tends to force the piston- 16 to, the. right and operating through rods 66 to turntheblades 2-2:in an. increasing pitch direction. Provision ismade for moving the thrust rod 68 by incorporating a regulator on the forward end of the sleeve extension 32 as is generally indicated by the reference numeral 10. This is; accomplished generally as indicated in Figs. 4 and. 5, wherein an annular plate 12 fits over the tubular extension 32' and is seated against a shoulder 1| at the juncture with the larger diameter 36, where it is secured by welding, brazing or the like,v as indicated at 1'3. Secured in the annular plate 12, such. as to be properly aligned with the lug 64 of the blade header, there is mounted one end of the tubular sleeve 68 which forms the. guide for the thrust rod 66, the tube 68 extending thru the side Wall of the tubular section 20 whereit is bonded or otherwise secured as indicated at T5. The push rod 66 extends forwardly of the annular plate 72. to securely and rigidly attach to a pistonhead 76 such as by means of-a lock nut 19. Helicalv springs 11 encompassing the rods 66 and engaging between the annular plate 12 and the piston 16 operate thereby normally to move the piston toward the left as viewed in Figs. 4 and 5. The piston 76 incorporates a guide sleeve and stop member 18 which is slidable along the tubular extension 322 to engage a ring 80 secured about the forward end of the tubular extension 32. A capmember 82 threads upon the tubular extension 32 such as at. 84 to engage the stop ring 8!]. The cap member incorporates a cylindrical portion 86 circumscribing the piston 16 and also has a skirt portion 88 embracing the periphery of the annular member. 12'. Fluid seal. rings 90 are incorporated in the junctures of the tubular sleeve 32 and the cap member 82 and between the latter and the periphery of the annular member 12 as Well as for the sliding engagement of the piston 16 on the tubular extension 32 and in cylinder Wall 86. Thus, there is provided an annular chamber of fluidtight character that is embraced by the tubular parts 32-, the cap member 82, and the annular member 12. This chamber is divided intotwo variable volume chambers 92' and 94 by the movable piston 16. For the purposes of convenience and subsequent reference 92- may be identified a the pressure chamber and 9.4 may be-identified as the reservoir.

Engagement of the stopmember 18 with the ring 8! defines the minimum volume of themessure chamber 92, and the minimum volume of the. reservoir 94 is determined by means of studs 95 threaded into the piston member is and locked in place by nuts 98-, the free end of the studs 96 being located within the reservoir 94 and adapted to engage the annular member l2'for limiting the proximity of the piston '56 with respect to the annular member 72. One limit of the blade angle shift is thereby determined by the stud. 96 since it determines the extent to which the rod 66 may push upon the lugs 64. The other limit of the blade shift range is determined by the engagement of the stopsleeve 18' with the ring 80; The spring H encompassing the rod 66 tends to move the piston 16 against the stop ring 86 thus reduc ing the resistance to the normal pitch shifting characteristic of the blade 22; If it is assumed that the natural tendenciesbuilt into the blades, and the contributing features of the regulator characterize a propeller-construction in which the blades during propeller rotation have a tendency to automatically shift to av high angle. position; then it will be observed that-a reduced blade angle may be obtained by altering the relative volumes of the chambers 92 and. 94". In the present instance, that alteration: is effected by means. of fluid pressure responsive mechanism provided by the regulator TB- substantially as shown by Figs. 5, 6 and 7.

The fluid pressure responsive mechanism herein disclosed see Figs. 5-, 6 and '7. comprises a governor valve unit sea connected by a fluid passage tea. with a flow sensitive valve Hi4 and: thence by fluid passage N16 to a fluid pump its contained within the reservoir 95 and all rigidly mounted upon the annular plate '72 substantially as in dicated in Fig. 6 and as schematically shown in Fig. 7. Referring to Fig. 6, the governor valve 599. comprises a chambered body He having a stepped bore receptive of aporting sleeve H2 that provides axially spaced ports H4 and H6 opening from the bore of. the sleeve. into channels lid and I29 in a bore of the body H0. The

member E2. by means of apertured lugs l2 2- and screw devices I24. The channel H8 in the body opens into the fluid passage I02. As shown in Fig. 5 the channel I20 opens into a short length of tubing I26 one end of which is secured in the body IIO and is so disposed as to extend parallel with the axis of rotation and through an aperture I28 of the piston head 16 where it is surrounded by a gland I30 to reduce fluid flow between the piston head and the outside of the tube. It will thus be seen that the channel I20 is always in communication with the pressure chamber 92.

For controlling communication between the channels H8 and I20, and hence between the fluid passage I02 and the pressure chamber 92 there is a spool valve I32 that is slidable along the bore of the porting sleeve I I2 and has a peripheral groove I34 adapted to bridge ports H4 and H6 when the spool valve I32 is in proper position. The spool valve is normally urged to a radially inward position by means of a spring I36 bottoming against a part of the spool valve and thrusting against an adjusting screw I38 mounted in the fixed sleeve I40 carried by a ring nut I42 threaded into the radially outer end of the bore of the body H0. The sleeve I40 incorporates a flange I fitting within the smallest bore of the body M0, the flange being apertured at I46 to provide passage of the exhaust fluid into a chamber I08 between the nut I02 and the flange I00 which opens by lateral bores I50 to the outside of the body H0 and hence into the reservoir 94.

From the foregoing it should be observable as shown in Figs. and 6 that pressure applied to the passage I02 is always present in the annular groove I34 surrounding the spool valve. If the spool valve is shifted radially outward, which is the position it obtains by centrifugal force upon manifestation of a certain propeller speed, that fluid pressure around the waste of the fluid valve is also present at the ports II6, channel I20, tubular passage I26 and in the pressure chamber 02. The effect of that pressure will tend to enlarge the pressure chamber 92 causing the piston 16 to move to the right and as illustrated in Figs. 4 and 5 by sliding upon the tube I26 and by pushing the rods 66 against the lugs 64 of the blades, during the time compressing the springs 11 until the stop members 96 engage the head member 12. It should also be observable that when the spool valve I32 occupies the radial inward position as shown in Fig. 6 that the pressurechamber 82 is thence in direct communication thru the tube I26, annular groove I20, port II6, the bore of the porting sleeve I I2, the apertures I46 of the flange I44, the chamber I48, and the lateral port I50 into the reservoir 94. The built-in characteristics of the blade 22, while the propeller is rotating, coupled with the tendency of the springs 11 tend to move the piston 16 toward the left and thereby to reduce the volume of the pressure chamber 92 which effects the drain of the fluid in that chamber thru the passages just described back into the reservoir 94.

The flow sensitive valve I04 is also mounted upon the plate 12 by means of the lugs I52 and screw devices I54 and incorporates a chambered body I55 with its longer axis disposed upon the radius of propeller rotation. A chamber I56 therein encloses a centrifugally responsive valve member I58 provided with spaced lands I60 and I62, the radially inward end of the casing I55 being opened at I64 to the reservoir 94 while the fluid passage I02 opens into the chamber I56 at 6.. I66 with the passage I06 opening into the end of the chamber at I68. The valve I58 is capable of freely moving from end to end of the chamber I56 and the lands are so spaced that an end face of the land I60 is always exposed to the fluid content of the passage I06 but may shift radially inward thereunder to close a port I10 that opens from the interior of the body to the reservoir 84, the port I10 being so positioned that it is in communication with the annular channel I12 separating the lands I60 and I62 when the pump is not operating, but is adapted to be closed by the land I60 when the pump delivery is applied against the end face of land I60. The land I60 is provided with a notch or restricted flow passage I13 that connects opposite sides of the land to permit a restricted or measured pump flow from the pump outlet I68 to the channel I12 between the lands and thence out the port I66 leading to the line I02 at all times. The cross section of the notch I13 is not large enough however but that there may be a balance between centrifugal force upon the valve I58 and pump pressure on the face of the land I60 so that a simulated regulator function, and sensitivity to both forces obtains when the pump is either started or stopped. Hence, when the valve I58 is in the radially outward position as shown in Fig. 6 the passage I02 is connected without obstruction to the exhaust port I10 and to the reservoir, and if the spool valve I32 of the governor valve is in the radially outward position, then the pressure chamber 92 is connected for drain-back into the reservoir thru the passage I82 and the exhaust port I10 of the flow sensitive valve. That is a condition that may ensue upon cessation of pump operation whereby no effective pressure is applied to the line I06, as will presently be explained. In this outward position of the valve I58 the end of the land I60 is always exposed to the pressure at the port I68, and if the pump I08 is operating then the force of the pressure in the chamber against the end face of land I60 will operate to shift the valve I58 radially inward against centrifugal force upon the valve due to rotation of the propeller. When that pressure overcomes the centrifugal force applied to the valve, the valve moves inward sufficient to close the port I10 and prevent return of the fluid to the reservoir. The port I66 is then open to pressure delivered by the pump into chamber I56 and notch I13 which flows to the groove I34 of the spool valve through I02, and thence on to the pressure chamber- 92 as has been explained.

In actual construction the flow sensitive valve may be built into or attached to the governor valve I00 and if desired a pressure relief valve may be inserted in the line I08 between the pump and the flow sensitive valve. Where the pressure relief valve is used it should be set at a blow-off value far enough above the pressure potential required for shifting the blades to the low pitch position that the efficiency of the regulator mechanism will not be impaired.

On the other hand, the flow sensitive valve may be built into or incorporated as a part of the pump structure I08, which is here shown as a conventional intermeshing gear type of pump comprising a chambered body I14 and plates I16 and I18 clamped together by screw devices I and mounted upon the plate 12 by means of bolts and spacers I82. Intermeshing gears I84 and I86, the latter of which is mounted on a shaft I88 operate to draw fluid in through the intake I90 and deliver it to the outlet passage I92 which 7 opens into'thepassage I 86.. Drive. for the, pump is provided byextending the shaft. I88 rear-i wardly' through a. tubular housing I94 extend ing from the plate 12 outside of the hub barrel 29' to an annular head member I98. of the power developing means. A fluid seal: I 99 is. pro;- vided. in the end of the tubular housing I94 to. prevent fluid leakage and. bushings; 2.04. provide: bearings for the shaft I88 Within the tubular housing I94. The aft end of the.- shaft. I88 ex.- tending from the member I98receivesa drivingv gear 29.6 which meshes with a. pump drivingggear 268' journalled on the rear" sleeve extension 3,4 thru the medium of a bearing bushing M8,; the; pumpdriving gear 288 being relatively fixed with the engine, or casing I9 because of a flared. skirt 2| 2. engaging a stop such as 2I4. Thus, it; will be observed that the rotation of, the propeller causes the gear 206 to roll about the; pump driving gear 288 when the latter is arrested against rotation.

The plate member I98 seats against a shoulder 216 of the rear hub extension 34 where it is secured by bonding or otherwise. The periphery of the plate I98 is channeled at M8 to receive a seal ring 2I9 engageable with a ledge in the rim 228 of a cover member 22I engaging about the periphery of the plate I98 and forming an annular chamber 200 enclosing the pump driving gear and. which usually carries an appropriate amount of lubricant for satisfactory operation of the elements. A snap ring 222 operates to retain the cover 22I upon the plate I98. An inward extension 224 of the cover provides a seal ring 226-engageable with the skirt, 2I2 to prevent loss of lubricant from the chamber 208. A shim 228 and a snap ring 230 operate to locate the bearing bushing 2H] and pump driving gear 288, while a seal device 232 disposed within the skirt 2I2 is held in place by a snap ring 2.34 and prevents loss of lubricant from inside the pump driving gear.

So long as the pump driving gear 208 is held stationary, or so long as the propeller and the gear casing is caused to rotate relative to the pumpdriving gear, the pump I08 will elfectively take up fluid from the reservoir 94 and discharge into the passage I06, flow sensitive valve I04 and passage I 02 to the governor valve I98 and thence, operate to shift the pitch of the. blades as hereinbefore described. In Fig. 4 there is shown means by the fixed lug 2H! for restraining the pump driving gear 298 from rotating. whereby the pump I 68 will be driven at all times that the propeller is rotating about the pump drive gear 208. In that instance, the lug. 2 IA cone. stantly engages within a notch 21.5, of the skirt 2I2. It is preferable however, that. the pump drive, gear 208 be selectively arrestable. which may be accomplished by means shown in Fig. 5, wherein the skirt 212 has a peripheral flange 248 which is notched at 252. and adapted to. 176-. ceive a detent 2 14 carriedv by a bell. crank 2'4'6 pivoted at 248 from some rigid part of the structure I and which bell crank may be rocked by means of a push-pull rod 256. By that construction rotation of the bell crank 246 in a clockwise direction withdraws the detent 244' from the notch 262 and permits the pump driving gear 288' to rotate with gear housing and consequently deliver no torque to the pump driving shaft I88. When it is desired to drive the pump, rotation of the bell crank 248 in a counterclockwise direction will drop the detent 284' into the notch 242 which will effectively hold the pump driving gear against rotation. As a; consequence;

the gear2il6 rolling about the pump driving gear 208 effects operation. of; the pump. 0n the other hand; the selection of driving'or nondriving. of: the pump I118. may be efiected as suggested in Fig. 7, where. the, pump driving gear 288 is carried by a hub 212a journalled on the shaft, I2 by: an anti-friction bearing 2I0a. The hub- ZIZa is: provided with a brake surface 252 adapted to be; engaged by afriction face; 254 carried by; an axially movable support 256". Obviously when the brake surfaces 252 and 254 are engaged the pump driving gear 288 will be arrested and the pumpltficaused tobe operated. However, separationof the brake surfaces permits the pump driving gear 298v to rotate with the hub and com sequently inactivates the pump I08.

Reverting to the assumption that-the natural tendencies of; the blade. plus its operative con nection with the control mechanism tend; automatically to shift the blades to the high pitch position, a slight, modification of accomplishing that end is illustrated in Fig. 7. The regulator. here comprises the cap 82a mounted on the tube extension 32 as in the preceding instance and providing a cylindrical bore cooperable with the. piston 16 attached to the stop sleeve 18 asheretofore.- In: this instance, the preloadinlg chamber 92 is charged to a high potential with compressed air or an inert gas admitted thru the filler valve 260 and which operates upon the movable piston it constantly forcing it toward the right in- Fig. 7 to push upon the rod 66 tending to rotate the blade element 64 in a counterclockwise direction so as to shift. the blad 22 intoa coarse pitch position as respects therotation of th propeller, indicated by the arrow 262. While the valve mechanism and pump may still be located in the reservoir 94 as heretofore explained, the illustration of Fig. 7 combines the regulator Itv and the pump driving gear 208 as contained in the reservoir, all for the purpose of clearly illustrating the operation of the construction.

The flowvv sensitive valve I04 and the governor valve I00, are both disposed such that their active elementv I58 and I32a respectively are subject to, radially outward, movementin response to centrifugal force. The passage I82 connecting the flow sensitive valve. with the governor valve has been shown as joining a passage 264 leading to piston chamber 95'. The governor valve I00 here shown as-a tubular casingprovides the port H4 to whichthe passage IE2 is connected and a spoolvalve [82a is kept within the tubular casing by abar or: pin 265 at the radially inward end and by an apertured disc 266; at the outer end, the latter of which supports. the adjustable spring. support I38 similar to that heretofore described. The peripheral groove I34 is always in communicationwith the port H4 and is adapted upon radially outward shifting of the valve I32 a toconnect I M with the lateral'port 268'opening into the reservoir;

A propeller constituted as herein disclosed provides a simple construction for a two-position condition of operation whereby the governor mechanism operates to control the blade for constant-speed operation at take off, and further provides for maximum pitch angle for cruising speed; With the propeller at rest or nonrotating the pump will be nonoperative and there will be no pressure potential in the regulator to move the piston 'IBtoward the low'pitch position. With respect to Figs. 4 to 6 the fluid. in the chamber 92 will have drained into the reservoir 94 while" with respect to Fig. '7 the preloading of the air or gas in the chamber 92 will have collapsed the chamber 95. In either event the blades 22 will have moved to their maximum pitch position. Upon driving of the propeller thru rotation of the shaft I2, the pump I08 produces pressure against the end face of the land 160 of the flow sensitive valve, and as soon as that pressure becomes great enough to overcome the centrifugal force exerted upon valve member I58 then the passage I02 is connected directly with the pump source which exposes the output of the pump to the governor valve I00. Centrifugal force operating upon the governor valve lllB of Figs. 4 to 6 if great enough connects the fluid passage N32 with the port H6 so that the chamber 92 is charged with pressure which effects movement of the piston 16 toward the right with a consequential rotation of the blades 22 in a pitch decreasing direction which is proper for take off and climb. According to Fig. '7 the governor valve I operates to deliver the pressure from the pump to the chamber 95 until such time as centrifugal force operative upon the valve member i320. opens a communication between ports H4 and 268. The parts are so constituted that it does not occur until the chamber 95 has been substantially filled with fluid to compress the chamber 92 permitting pitch shift of the blades 22 to a small angle suitable for take off and climbing. With the occurrence of a smaller angle of blade pitch the driving engine speeds up because of the lesser load and consequently drives the propeller at a faster rate, centrifugal force acting upon the valve member I32 moves it radially outward so as to connect the ports [l4 and 268, which allows the compressed air or gas in the chamber 92 to dominate and increase the pitch of the blade.

Upon attaining the position aloft desired the means holding the pumpdriving gear against rotation is releasedwhich causes cessation of operation of the pump with a consequent diminution of pressure in the pressure line and which permits the blade in both instances to shift to the greatest angle of its range. Increasing the pitch of the blade immediately slows down the rotating speed of the propeller lessening the centrifugal effect upon the speed responsive elements such that the flow sensitive valve is allowed to r connect the ports [66 and I and the governor valve is permitted to open the drain ports into the reservoir. When the brake of the device is applied, such that the pump is operated, then the regulator mechanism operates upon the blade to maintain constant speed. When the arresting device for the pump driving gear is released, the pump becomes inoperative and the propeller blades automatically shift to the high pitch position which is suitable for cruising.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A pitch shiftable propeller, comprising in combination, a hub sleeve adapted to be rotated by a shaft and having fore and aft tubular extensions, a socket sleeve adapted to rotatably support propeller blades for pitch shifting movement, said socket sleeve having a transverse bore receptive of the hub sleeve and bonded thereto such that the ends of the socket sleeve extend radially from the bore of the hub sleeve, and

such that the tubular extensions of the hub sleeve extend fore and aft of the socket sleeve, a pair of annular plates secured about the hub sleeve extensions adjacent the socket sleeve, a pair of hollow cap members secured one about each annular plate and hub sleeve extension to cooperate with the respective sleeve extension and annular plate to provide annular chambers fore and aft of the socket sleeve, an annular piston movable within the fore chamber, means connected with the piston for rotating the pitch shiftable blades, fluid pressure responsive means within the fore chamber for moving fluid from one side of the piston to the other side thereof, and means in the aft chamber and extending into the fore chamber for activating the pressure responsive means. I

2. The combination set forth in claim 1 wherein the means for activating the pressure responsive means includes a sleeve relatively rotatable with respect to the aft chamber and a fluid pump, said sleeve extending into the aft chamber and driving said pump.

3. In a shiftable pitch propeller having blades tending to shift to the pitch increase position when the propeller is rotating, the combination comprising, a casing on the propellerproviding an annular cylinder circumscribing the axis of propeller rotation, an annular piston movable within the cylinder dividing it into a reservoir and a pressure compartment, said piston having mechanical linkage with the blades to be moved thereby, a governor valvemounted on the casing inside of the reservoir, passage means secured to the valve and slidably extending through the piston to .communicate with-the pressure compartment and the governor valve, a fluid pressure pump carried by the casing, within the reservoir and having fluid connection with the governor valve, a flow control valve inserted in said connections for connecting and disconnecting the pump delivery to the governor valve and reservoir, and selectively operable means for operating the pumpupon rotation of the propeller, whereby operation of the. pump forces fluid under pressure to flow through .the governor valve to the pressure compartment-for opposing the tendency of the blades to shift/to the pitch increase position. v

4. The combination set forth in .claim 3, wherein the flow control valve includes a casing and plunger disposed radially of the reservoir, said plunger having an end face exposed to the flow from the pump in opposition to centrifugal force acting upon the plunger.

5. In a variable pitch propeller, a hub supporting a plurality of blades for pitch shifting movement and having tubular extensions fore and aft of the blades, a casing mounted on and cooperating with the fore extension to provide an annular regulator, an annular piston movable within the regulator to divide the chamber enclosed by the casing and fore extension into a reservoir and a pressure chamber, a fluid pressure pump and control valves mounted within the reservoir, passage means extending from one of the control valves into the pressure chamber, a casing mounted on and cooperating with the aft extension to provide a gear casing, a ring gear journalled within the second mentioned casing and having a flange extending without the said casing, means for arresting and releasing the ring gear for selective rotation with respect to the gear casing, transmission means connecting the ring gear in the gear casing with the pump in the reservoirof the firstm'entiane'a cas ng, a tubular hcusing joiningthe' fofe and'a'ft casings to enclose the transmission means, and thrust means connecting the 'pistcn with the blades so that movement of the piston is transmitted to pitch 'shifting mbvement of the blades.

6. The combination set ferth in claim 5, wherein the control valves include 'po'rtedc'asin g's with movable plungersres'ponsive to centrifugal force normally tending to open the pressure chamber to drainback to the reservoir, and one of said control "valvesb'ei'ng a flow sensitive valve responsive to pump operation for closing the drain back to the reservoir and for connecting the pump -delivery to the pressure chamber so that the blades may be shifted in pitch during the pump operation.

7. The combination set forth in claim 5 wherein the control valves include a governor valve interconnected with a how sensitive valve and responsive to increase of centrifugal 'force effecting a decrease bf 'bla'd'e pitch, said new sensitive valve including a 'ceiitri'fug'ally respjons'ive'elerfient tending to connect the'bu fnb'outlet t6 the-reservoir, and sensitive to pump output for erasing the outlet to the feservoirehd for-eonne't'i'n'g the pump auteur to thejpre'ssiir'bhann ber, iar-decreasing the blade pitch.

8. In a centrolle'r for aircraft "hai'z'ing a p'iofiell'e'r with pitch-*shiftable blades 'normeuy seeking an'increased pitch position, the 'corhbination indludihg, a Chamber attached to "Said pro eller and "rotatable there'with, a movable partition separating the chamber into a pressure eompar't- V "merit and a'resei v ir *cbn psrtment, means ';en-- nectin'g the partition with the pitch shiftable blades and responsive "in movement to movement of "the blades in a pitch shifting sense, valve means mouhtedbh one wall of the reservoir compartment for controlling the new of fluid from one Compartment into the '-other, pressure developing means mounted on one wall of the reservoir compartment and rotatable therewith 'for' applying "fiui'd under pressure to the valve means, drive means operatively connected to said. pressure developing means for operating the same up'o'nielative "rotation betweensaid drive means and said compartment and selecting means including releasable rotation restraining means operatively connected 'to said drive mean-sand n' i-ounte'd on non-rotatable structure fbr indeiih'g the pressure 'aeveleping means 'cper'ative and inoperative, said valve means when the pressure developing means are rendered operative gcverning the new o'f'pres'sure fluid 'to and from the pressure compartment.

'9. The combination set forth in claim 8 wherethe releasable rotation restraining means includes 'a rotatably journalled member having a notched flange that is adapted to be engaged by "a hon-rotatable detent member to thereby render the fluid pressure developing means operative.

10. The combination set forth in claim 8 wherein the releasable rotati'on restraining means includes a rotatably -J'ournal1ed member having a friction surface that is adapted to be engaged by a non-rotatable friction surfaced member to thereby render the fluid pressure devel'opmg means operative.

KENNETH L. BERNINGER. JOHN F. REFERENCES CITED The following references "are of record in the file of this patent:

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